1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/debugfs.h>
4 #include <linux/slab.h>
5 #include <linux/uaccess.h>
6 #include <linux/memblock.h>
7 #include <linux/stacktrace.h>
8 #include <linux/page_owner.h>
9 #include <linux/jump_label.h>
10 #include <linux/migrate.h>
11 #include <linux/stackdepot.h>
12 #include <linux/seq_file.h>
13 #include <linux/memcontrol.h>
14 #include <linux/sched/clock.h>
19 * TODO: teach PAGE_OWNER_STACK_DEPTH (__dump_page_owner and save_stack)
20 * to use off stack temporal storage
22 #define PAGE_OWNER_STACK_DEPTH (16)
26 short last_migrate_reason;
28 depot_stack_handle_t handle;
29 depot_stack_handle_t free_handle;
32 char comm[TASK_COMM_LEN];
40 struct stack_record *stack_record;
43 static struct stack dummy_stack;
44 static struct stack failure_stack;
45 static struct stack *stack_list;
46 static DEFINE_SPINLOCK(stack_list_lock);
48 static bool page_owner_enabled __initdata;
49 DEFINE_STATIC_KEY_FALSE(page_owner_inited);
51 static depot_stack_handle_t dummy_handle;
52 static depot_stack_handle_t failure_handle;
53 static depot_stack_handle_t early_handle;
55 static void init_early_allocated_pages(void);
57 static inline void set_current_in_page_owner(void)
62 * We might need to allocate more memory from page_owner code, so make
63 * sure to signal it in order to avoid recursion.
65 current->in_page_owner = 1;
68 static inline void unset_current_in_page_owner(void)
70 current->in_page_owner = 0;
73 static int __init early_page_owner_param(char *buf)
75 int ret = kstrtobool(buf, &page_owner_enabled);
77 if (page_owner_enabled)
78 stack_depot_request_early_init();
82 early_param("page_owner", early_page_owner_param);
84 static __init bool need_page_owner(void)
86 return page_owner_enabled;
89 static __always_inline depot_stack_handle_t create_dummy_stack(void)
91 unsigned long entries[4];
92 unsigned int nr_entries;
94 nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 0);
95 return stack_depot_save(entries, nr_entries, GFP_KERNEL);
98 static noinline void register_dummy_stack(void)
100 dummy_handle = create_dummy_stack();
103 static noinline void register_failure_stack(void)
105 failure_handle = create_dummy_stack();
108 static noinline void register_early_stack(void)
110 early_handle = create_dummy_stack();
113 static __init void init_page_owner(void)
115 if (!page_owner_enabled)
118 register_dummy_stack();
119 register_failure_stack();
120 register_early_stack();
121 static_branch_enable(&page_owner_inited);
122 init_early_allocated_pages();
123 /* Initialize dummy and failure stacks and link them to stack_list */
124 dummy_stack.stack_record = __stack_depot_get_stack_record(dummy_handle);
125 failure_stack.stack_record = __stack_depot_get_stack_record(failure_handle);
126 if (dummy_stack.stack_record)
127 refcount_set(&dummy_stack.stack_record->count, 1);
128 if (failure_stack.stack_record)
129 refcount_set(&failure_stack.stack_record->count, 1);
130 dummy_stack.next = &failure_stack;
131 stack_list = &dummy_stack;
134 struct page_ext_operations page_owner_ops = {
135 .size = sizeof(struct page_owner),
136 .need = need_page_owner,
137 .init = init_page_owner,
138 .need_shared_flags = true,
141 static inline struct page_owner *get_page_owner(struct page_ext *page_ext)
143 return page_ext_data(page_ext, &page_owner_ops);
146 static noinline depot_stack_handle_t save_stack(gfp_t flags)
148 unsigned long entries[PAGE_OWNER_STACK_DEPTH];
149 depot_stack_handle_t handle;
150 unsigned int nr_entries;
152 if (current->in_page_owner)
155 set_current_in_page_owner();
156 nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 2);
157 handle = stack_depot_save(entries, nr_entries, flags);
159 handle = failure_handle;
160 unset_current_in_page_owner();
165 static void add_stack_record_to_list(struct stack_record *stack_record,
171 /* Filter gfp_mask the same way stackdepot does, for consistency */
172 gfp_mask &= ~GFP_ZONEMASK;
173 gfp_mask &= (GFP_ATOMIC | GFP_KERNEL);
174 gfp_mask |= __GFP_NOWARN;
176 set_current_in_page_owner();
177 stack = kmalloc(sizeof(*stack), gfp_mask);
179 unset_current_in_page_owner();
182 unset_current_in_page_owner();
184 stack->stack_record = stack_record;
187 spin_lock_irqsave(&stack_list_lock, flags);
188 stack->next = stack_list;
190 * This pairs with smp_load_acquire() from function
191 * stack_start(). This guarantees that stack_start()
192 * will see an updated stack_list before starting to
195 smp_store_release(&stack_list, stack);
196 spin_unlock_irqrestore(&stack_list_lock, flags);
199 static void inc_stack_record_count(depot_stack_handle_t handle, gfp_t gfp_mask)
201 struct stack_record *stack_record = __stack_depot_get_stack_record(handle);
207 * New stack_record's that do not use STACK_DEPOT_FLAG_GET start
208 * with REFCOUNT_SATURATED to catch spurious increments of their
210 * Since we do not use STACK_DEPOT_FLAG_GET API, let us
211 * set a refcount of 1 ourselves.
213 if (refcount_read(&stack_record->count) == REFCOUNT_SATURATED) {
214 int old = REFCOUNT_SATURATED;
216 if (atomic_try_cmpxchg_relaxed(&stack_record->count.refs, &old, 1))
217 /* Add the new stack_record to our list */
218 add_stack_record_to_list(stack_record, gfp_mask);
220 refcount_inc(&stack_record->count);
223 static void dec_stack_record_count(depot_stack_handle_t handle)
225 struct stack_record *stack_record = __stack_depot_get_stack_record(handle);
228 refcount_dec(&stack_record->count);
231 void __reset_page_owner(struct page *page, unsigned short order)
234 struct page_ext *page_ext;
235 depot_stack_handle_t handle;
236 depot_stack_handle_t alloc_handle;
237 struct page_owner *page_owner;
238 u64 free_ts_nsec = local_clock();
240 page_ext = page_ext_get(page);
241 if (unlikely(!page_ext))
244 page_owner = get_page_owner(page_ext);
245 alloc_handle = page_owner->handle;
247 handle = save_stack(GFP_NOWAIT | __GFP_NOWARN);
248 for (i = 0; i < (1 << order); i++) {
249 __clear_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags);
250 page_owner->free_handle = handle;
251 page_owner->free_ts_nsec = free_ts_nsec;
252 page_owner->free_pid = current->pid;
253 page_owner->free_tgid = current->tgid;
254 page_ext = page_ext_next(page_ext);
255 page_owner = get_page_owner(page_ext);
257 page_ext_put(page_ext);
258 if (alloc_handle != early_handle)
260 * early_handle is being set as a handle for all those
261 * early allocated pages. See init_pages_in_zone().
262 * Since their refcount is not being incremented because
263 * the machinery is not ready yet, we cannot decrement
264 * their refcount either.
266 dec_stack_record_count(alloc_handle);
269 static inline void __set_page_owner_handle(struct page_ext *page_ext,
270 depot_stack_handle_t handle,
271 unsigned short order, gfp_t gfp_mask)
273 struct page_owner *page_owner;
275 u64 ts_nsec = local_clock();
277 for (i = 0; i < (1 << order); i++) {
278 page_owner = get_page_owner(page_ext);
279 page_owner->handle = handle;
280 page_owner->order = order;
281 page_owner->gfp_mask = gfp_mask;
282 page_owner->last_migrate_reason = -1;
283 page_owner->pid = current->pid;
284 page_owner->tgid = current->tgid;
285 page_owner->ts_nsec = ts_nsec;
286 strscpy(page_owner->comm, current->comm,
287 sizeof(page_owner->comm));
288 __set_bit(PAGE_EXT_OWNER, &page_ext->flags);
289 __set_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags);
291 page_ext = page_ext_next(page_ext);
295 noinline void __set_page_owner(struct page *page, unsigned short order,
298 struct page_ext *page_ext;
299 depot_stack_handle_t handle;
301 handle = save_stack(gfp_mask);
303 page_ext = page_ext_get(page);
304 if (unlikely(!page_ext))
306 __set_page_owner_handle(page_ext, handle, order, gfp_mask);
307 page_ext_put(page_ext);
308 inc_stack_record_count(handle, gfp_mask);
311 void __set_page_owner_migrate_reason(struct page *page, int reason)
313 struct page_ext *page_ext = page_ext_get(page);
314 struct page_owner *page_owner;
316 if (unlikely(!page_ext))
319 page_owner = get_page_owner(page_ext);
320 page_owner->last_migrate_reason = reason;
321 page_ext_put(page_ext);
324 void __split_page_owner(struct page *page, int old_order, int new_order)
327 struct page_ext *page_ext = page_ext_get(page);
328 struct page_owner *page_owner;
330 if (unlikely(!page_ext))
333 for (i = 0; i < (1 << old_order); i++) {
334 page_owner = get_page_owner(page_ext);
335 page_owner->order = new_order;
336 page_ext = page_ext_next(page_ext);
338 page_ext_put(page_ext);
341 void __folio_copy_owner(struct folio *newfolio, struct folio *old)
343 struct page_ext *old_ext;
344 struct page_ext *new_ext;
345 struct page_owner *old_page_owner, *new_page_owner;
347 old_ext = page_ext_get(&old->page);
348 if (unlikely(!old_ext))
351 new_ext = page_ext_get(&newfolio->page);
352 if (unlikely(!new_ext)) {
353 page_ext_put(old_ext);
357 old_page_owner = get_page_owner(old_ext);
358 new_page_owner = get_page_owner(new_ext);
359 new_page_owner->order = old_page_owner->order;
360 new_page_owner->gfp_mask = old_page_owner->gfp_mask;
361 new_page_owner->last_migrate_reason =
362 old_page_owner->last_migrate_reason;
363 new_page_owner->handle = old_page_owner->handle;
364 new_page_owner->pid = old_page_owner->pid;
365 new_page_owner->tgid = old_page_owner->tgid;
366 new_page_owner->free_pid = old_page_owner->free_pid;
367 new_page_owner->free_tgid = old_page_owner->free_tgid;
368 new_page_owner->ts_nsec = old_page_owner->ts_nsec;
369 new_page_owner->free_ts_nsec = old_page_owner->ts_nsec;
370 strcpy(new_page_owner->comm, old_page_owner->comm);
373 * We don't clear the bit on the old folio as it's going to be freed
374 * after migration. Until then, the info can be useful in case of
375 * a bug, and the overall stats will be off a bit only temporarily.
376 * Also, migrate_misplaced_transhuge_page() can still fail the
377 * migration and then we want the old folio to retain the info. But
378 * in that case we also don't need to explicitly clear the info from
379 * the new page, which will be freed.
381 __set_bit(PAGE_EXT_OWNER, &new_ext->flags);
382 __set_bit(PAGE_EXT_OWNER_ALLOCATED, &new_ext->flags);
383 page_ext_put(new_ext);
384 page_ext_put(old_ext);
387 void pagetypeinfo_showmixedcount_print(struct seq_file *m,
388 pg_data_t *pgdat, struct zone *zone)
391 struct page_ext *page_ext;
392 struct page_owner *page_owner;
393 unsigned long pfn, block_end_pfn;
394 unsigned long end_pfn = zone_end_pfn(zone);
395 unsigned long count[MIGRATE_TYPES] = { 0, };
396 int pageblock_mt, page_mt;
399 /* Scan block by block. First and last block may be incomplete */
400 pfn = zone->zone_start_pfn;
403 * Walk the zone in pageblock_nr_pages steps. If a page block spans
404 * a zone boundary, it will be double counted between zones. This does
405 * not matter as the mixed block count will still be correct
407 for (; pfn < end_pfn; ) {
408 page = pfn_to_online_page(pfn);
410 pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
414 block_end_pfn = pageblock_end_pfn(pfn);
415 block_end_pfn = min(block_end_pfn, end_pfn);
417 pageblock_mt = get_pageblock_migratetype(page);
419 for (; pfn < block_end_pfn; pfn++) {
420 /* The pageblock is online, no need to recheck. */
421 page = pfn_to_page(pfn);
423 if (page_zone(page) != zone)
426 if (PageBuddy(page)) {
427 unsigned long freepage_order;
429 freepage_order = buddy_order_unsafe(page);
430 if (freepage_order <= MAX_PAGE_ORDER)
431 pfn += (1UL << freepage_order) - 1;
435 if (PageReserved(page))
438 page_ext = page_ext_get(page);
439 if (unlikely(!page_ext))
442 if (!test_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags))
443 goto ext_put_continue;
445 page_owner = get_page_owner(page_ext);
446 page_mt = gfp_migratetype(page_owner->gfp_mask);
447 if (pageblock_mt != page_mt) {
448 if (is_migrate_cma(pageblock_mt))
449 count[MIGRATE_MOVABLE]++;
451 count[pageblock_mt]++;
454 page_ext_put(page_ext);
457 pfn += (1UL << page_owner->order) - 1;
459 page_ext_put(page_ext);
464 seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
465 for (i = 0; i < MIGRATE_TYPES; i++)
466 seq_printf(m, "%12lu ", count[i]);
471 * Looking for memcg information and print it out
473 static inline int print_page_owner_memcg(char *kbuf, size_t count, int ret,
477 unsigned long memcg_data;
478 struct mem_cgroup *memcg;
483 memcg_data = READ_ONCE(page->memcg_data);
487 if (memcg_data & MEMCG_DATA_OBJCGS)
488 ret += scnprintf(kbuf + ret, count - ret,
489 "Slab cache page\n");
491 memcg = page_memcg_check(page);
495 online = (memcg->css.flags & CSS_ONLINE);
496 cgroup_name(memcg->css.cgroup, name, sizeof(name));
497 ret += scnprintf(kbuf + ret, count - ret,
498 "Charged %sto %smemcg %s\n",
499 PageMemcgKmem(page) ? "(via objcg) " : "",
500 online ? "" : "offline ",
504 #endif /* CONFIG_MEMCG */
510 print_page_owner(char __user *buf, size_t count, unsigned long pfn,
511 struct page *page, struct page_owner *page_owner,
512 depot_stack_handle_t handle)
514 int ret, pageblock_mt, page_mt;
517 count = min_t(size_t, count, PAGE_SIZE);
518 kbuf = kmalloc(count, GFP_KERNEL);
522 ret = scnprintf(kbuf, count,
523 "Page allocated via order %u, mask %#x(%pGg), pid %d, tgid %d (%s), ts %llu ns\n",
524 page_owner->order, page_owner->gfp_mask,
525 &page_owner->gfp_mask, page_owner->pid,
526 page_owner->tgid, page_owner->comm,
527 page_owner->ts_nsec);
529 /* Print information relevant to grouping pages by mobility */
530 pageblock_mt = get_pageblock_migratetype(page);
531 page_mt = gfp_migratetype(page_owner->gfp_mask);
532 ret += scnprintf(kbuf + ret, count - ret,
533 "PFN 0x%lx type %s Block %lu type %s Flags %pGp\n",
535 migratetype_names[page_mt],
536 pfn >> pageblock_order,
537 migratetype_names[pageblock_mt],
540 ret += stack_depot_snprint(handle, kbuf + ret, count - ret, 0);
544 if (page_owner->last_migrate_reason != -1) {
545 ret += scnprintf(kbuf + ret, count - ret,
546 "Page has been migrated, last migrate reason: %s\n",
547 migrate_reason_names[page_owner->last_migrate_reason]);
550 ret = print_page_owner_memcg(kbuf, count, ret, page);
552 ret += snprintf(kbuf + ret, count - ret, "\n");
556 if (copy_to_user(buf, kbuf, ret))
567 void __dump_page_owner(const struct page *page)
569 struct page_ext *page_ext = page_ext_get((void *)page);
570 struct page_owner *page_owner;
571 depot_stack_handle_t handle;
575 if (unlikely(!page_ext)) {
576 pr_alert("There is not page extension available.\n");
580 page_owner = get_page_owner(page_ext);
581 gfp_mask = page_owner->gfp_mask;
582 mt = gfp_migratetype(gfp_mask);
584 if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags)) {
585 pr_alert("page_owner info is not present (never set?)\n");
586 page_ext_put(page_ext);
590 if (test_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags))
591 pr_alert("page_owner tracks the page as allocated\n");
593 pr_alert("page_owner tracks the page as freed\n");
595 pr_alert("page last allocated via order %u, migratetype %s, gfp_mask %#x(%pGg), pid %d, tgid %d (%s), ts %llu, free_ts %llu\n",
596 page_owner->order, migratetype_names[mt], gfp_mask, &gfp_mask,
597 page_owner->pid, page_owner->tgid, page_owner->comm,
598 page_owner->ts_nsec, page_owner->free_ts_nsec);
600 handle = READ_ONCE(page_owner->handle);
602 pr_alert("page_owner allocation stack trace missing\n");
604 stack_depot_print(handle);
606 handle = READ_ONCE(page_owner->free_handle);
608 pr_alert("page_owner free stack trace missing\n");
610 pr_alert("page last free pid %d tgid %d stack trace:\n",
611 page_owner->free_pid, page_owner->free_tgid);
612 stack_depot_print(handle);
615 if (page_owner->last_migrate_reason != -1)
616 pr_alert("page has been migrated, last migrate reason: %s\n",
617 migrate_reason_names[page_owner->last_migrate_reason]);
618 page_ext_put(page_ext);
622 read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos)
626 struct page_ext *page_ext;
627 struct page_owner *page_owner;
628 depot_stack_handle_t handle;
630 if (!static_branch_unlikely(&page_owner_inited))
638 /* Find a valid PFN or the start of a MAX_ORDER_NR_PAGES area */
639 while (!pfn_valid(pfn) && (pfn & (MAX_ORDER_NR_PAGES - 1)) != 0)
642 /* Find an allocated page */
643 for (; pfn < max_pfn; pfn++) {
645 * This temporary page_owner is required so
646 * that we can avoid the context switches while holding
647 * the rcu lock and copying the page owner information to
648 * user through copy_to_user() or GFP_KERNEL allocations.
650 struct page_owner page_owner_tmp;
653 * If the new page is in a new MAX_ORDER_NR_PAGES area,
654 * validate the area as existing, skip it if not
656 if ((pfn & (MAX_ORDER_NR_PAGES - 1)) == 0 && !pfn_valid(pfn)) {
657 pfn += MAX_ORDER_NR_PAGES - 1;
661 page = pfn_to_page(pfn);
662 if (PageBuddy(page)) {
663 unsigned long freepage_order = buddy_order_unsafe(page);
665 if (freepage_order <= MAX_PAGE_ORDER)
666 pfn += (1UL << freepage_order) - 1;
670 page_ext = page_ext_get(page);
671 if (unlikely(!page_ext))
675 * Some pages could be missed by concurrent allocation or free,
676 * because we don't hold the zone lock.
678 if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags))
679 goto ext_put_continue;
682 * Although we do have the info about past allocation of free
683 * pages, it's not relevant for current memory usage.
685 if (!test_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags))
686 goto ext_put_continue;
688 page_owner = get_page_owner(page_ext);
691 * Don't print "tail" pages of high-order allocations as that
692 * would inflate the stats.
694 if (!IS_ALIGNED(pfn, 1 << page_owner->order))
695 goto ext_put_continue;
698 * Access to page_ext->handle isn't synchronous so we should
699 * be careful to access it.
701 handle = READ_ONCE(page_owner->handle);
703 goto ext_put_continue;
705 /* Record the next PFN to read in the file offset */
708 page_owner_tmp = *page_owner;
709 page_ext_put(page_ext);
710 return print_page_owner(buf, count, pfn, page,
711 &page_owner_tmp, handle);
713 page_ext_put(page_ext);
719 static loff_t lseek_page_owner(struct file *file, loff_t offset, int orig)
723 file->f_pos = offset;
726 file->f_pos += offset;
734 static void init_pages_in_zone(pg_data_t *pgdat, struct zone *zone)
736 unsigned long pfn = zone->zone_start_pfn;
737 unsigned long end_pfn = zone_end_pfn(zone);
738 unsigned long count = 0;
741 * Walk the zone in pageblock_nr_pages steps. If a page block spans
742 * a zone boundary, it will be double counted between zones. This does
743 * not matter as the mixed block count will still be correct
745 for (; pfn < end_pfn; ) {
746 unsigned long block_end_pfn;
748 if (!pfn_valid(pfn)) {
749 pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
753 block_end_pfn = pageblock_end_pfn(pfn);
754 block_end_pfn = min(block_end_pfn, end_pfn);
756 for (; pfn < block_end_pfn; pfn++) {
757 struct page *page = pfn_to_page(pfn);
758 struct page_ext *page_ext;
760 if (page_zone(page) != zone)
764 * To avoid having to grab zone->lock, be a little
765 * careful when reading buddy page order. The only
766 * danger is that we skip too much and potentially miss
767 * some early allocated pages, which is better than
768 * heavy lock contention.
770 if (PageBuddy(page)) {
771 unsigned long order = buddy_order_unsafe(page);
773 if (order > 0 && order <= MAX_PAGE_ORDER)
774 pfn += (1UL << order) - 1;
778 if (PageReserved(page))
781 page_ext = page_ext_get(page);
782 if (unlikely(!page_ext))
785 /* Maybe overlapping zone */
786 if (test_bit(PAGE_EXT_OWNER, &page_ext->flags))
787 goto ext_put_continue;
789 /* Found early allocated page */
790 __set_page_owner_handle(page_ext, early_handle,
794 page_ext_put(page_ext);
799 pr_info("Node %d, zone %8s: page owner found early allocated %lu pages\n",
800 pgdat->node_id, zone->name, count);
803 static void init_zones_in_node(pg_data_t *pgdat)
806 struct zone *node_zones = pgdat->node_zones;
808 for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
809 if (!populated_zone(zone))
812 init_pages_in_zone(pgdat, zone);
816 static void init_early_allocated_pages(void)
820 for_each_online_pgdat(pgdat)
821 init_zones_in_node(pgdat);
824 static const struct file_operations proc_page_owner_operations = {
825 .read = read_page_owner,
826 .llseek = lseek_page_owner,
829 static void *stack_start(struct seq_file *m, loff_t *ppos)
838 * This pairs with smp_store_release() from function
839 * add_stack_record_to_list(), so we get a consistent
840 * value of stack_list.
842 stack = smp_load_acquire(&stack_list);
853 static void *stack_next(struct seq_file *m, void *v, loff_t *ppos)
855 struct stack *stack = v;
858 *ppos = stack ? *ppos + 1 : -1UL;
864 static unsigned long page_owner_stack_threshold;
866 static int stack_print(struct seq_file *m, void *v)
869 struct stack *stack = v;
870 unsigned long *entries;
871 unsigned long nr_entries;
872 struct stack_record *stack_record = stack->stack_record;
874 if (!stack->stack_record)
877 nr_entries = stack_record->size;
878 entries = stack_record->entries;
879 stack_count = refcount_read(&stack_record->count) - 1;
881 if (stack_count < 1 || stack_count < page_owner_stack_threshold)
884 for (i = 0; i < nr_entries; i++)
885 seq_printf(m, " %pS\n", (void *)entries[i]);
886 seq_printf(m, "stack_count: %d\n\n", stack_count);
891 static void stack_stop(struct seq_file *m, void *v)
895 static const struct seq_operations page_owner_stack_op = {
896 .start = stack_start,
902 static int page_owner_stack_open(struct inode *inode, struct file *file)
904 return seq_open_private(file, &page_owner_stack_op, 0);
907 static const struct file_operations page_owner_stack_operations = {
908 .open = page_owner_stack_open,
911 .release = seq_release,
914 static int page_owner_threshold_get(void *data, u64 *val)
916 *val = READ_ONCE(page_owner_stack_threshold);
920 static int page_owner_threshold_set(void *data, u64 val)
922 WRITE_ONCE(page_owner_stack_threshold, val);
926 DEFINE_SIMPLE_ATTRIBUTE(proc_page_owner_threshold, &page_owner_threshold_get,
927 &page_owner_threshold_set, "%llu");
930 static int __init pageowner_init(void)
934 if (!static_branch_unlikely(&page_owner_inited)) {
935 pr_info("page_owner is disabled\n");
939 debugfs_create_file("page_owner", 0400, NULL, NULL,
940 &proc_page_owner_operations);
941 dir = debugfs_create_dir("page_owner_stacks", NULL);
942 debugfs_create_file("show_stacks", 0400, dir, NULL,
943 &page_owner_stack_operations);
944 debugfs_create_file("count_threshold", 0600, dir, NULL,
945 &proc_page_owner_threshold);
949 late_initcall(pageowner_init)